Sliding window lock

ABSTRACT

A lock assembly for a horizontal sliding sashless window is provided. The lock assembly comprises a block having anchor means, and pivotal attachment means. The block has a vertical lock surface formed to block the leading edge of the sliding pane when the sliding pane is in closed position, with clearance to permit pivotal movement of the lock surface away from the sliding pane. The pivotal attachment means attaches the block to the sill of the window at a position forwardly offset from the lock surface of the block, and provides for limited vertical movement of the block away from the sill. The anchor means is selectably engageable and releasable by the combination of pivoting the block and by motion away from the sill. The lift and twist motion of the lock assembly does not limit the height of the block or the depth of the anchor means.

BACKGROUND OF THE INVENTION

This invention relates to lock assemblies for securing sliding closuresagainst forced entry, and more particularly to a lock assembly forsecuring sashless horizontal sliding windows.

BACKGROUND OF THE INVENTION

Sashless sliding windows are notorious for offering poor resistance toforced entry. It is often possible to open and gain entry through suchwindows, without breaking the glass, by manipulating the locking meansand/or window assembly with a knife, spatula, coat hanger or the like.It is, of course, difficult to lock a sashless window, since this typeof window lacks a wooden or metal sash or other means for convenientlyattaching part of a locking assembly.

Rather primitive expedients have been used in attempts to effectivelysecure sashless windows. For instance, it is known to wedge a stick ofsuitable length along the bottom of the fixed panel between the windowjamb and the leading edge of the sliding panel. A locking means of thisnature not only provides inadequate security against forced entry byprofessional burglars, but is also bulky, unsightly and prone to beingmisplaced in time.

Somewhat less primitive locking means are commercially available. Acondensation lock having a surface which pushes the sliding pane againstthe fixed pane is one such means. One type of condensation lock has aU-shaped plastic body which is designed to be pivoted by hand towardsthe face of the sliding pane, to force that pane against the fixed pane.A window so locked can, however, be pried open by inserting a screwdriver or the like between the jamb and the sliding pane so as to applya sufficient lateral force (a force directed along the plane of slidingaction) to the sliding pane to force it past the surface of contact ofthe condensation lock.

Another common commercially available lock means for a sashless windowcomprises a U-shaped body designed to overlap both sides of the slidingpane at a vertical edge, the U-shaped body having an inwardly directedflange which cooperates with a lever attached to the inside of the jambto provide resistance to a lateral force. This type of lock can,however, be circumvented in a number of ways. For instance, the portionof the lock assembly affixed to the glass pane can usually be forceablyslid down or up past the point of contact with the lever portion.

Also known is a lever-action type of lock which is designed to bemounted on the inside of the window sill near the area of pane overlap,having a surface which blocks the leading edge of the sliding paneagainst lateral movement thereof. A lock of this nature is disclosed inCanadian Pat. No. 547,454, which issued to Harold Sisson on Oct. 15,1957. This type of lever-action design suffers, however, from a numberof apparent drawbacks. Because this type of lock must be manipulated bymeans of a lever type action, i.e. one end of the major body beingraised while the other end remains virtually satisfactory, certaindimensions of the lock components are limited, due to clearanceproblems. The height of the major body is necessarily limited to only afraction of an inch, since an overly large major body would not clearthe edge of the sliding pane during the pivoting operation. Also limitedis the depth of the anchor located at the end of the major body remotefrom the pivot point, due to limited clearance during operation betweenthe bottom of the one end of the major body and the top of the sill ormounting bracket. These limitations reduce the effectiveness of thelever-action lock mechanism against forced entry. The Sisson lock alsohas the disadvantage of being composed of a large number of componentparts.

SUMMARY OF THE INVENTION

It has been found that the disadvantages of known lock assemblies forsashless horizontal sliding windows may be overcome by a lock assemblywhich utilizes a lift and twist type of motion, since such a motion doesnot limit the height of the major body or the depth of the anchor means.

Accordingly, the present invention provides a lock assembly for asliding closure having a fixed panel and a sliding panel mounted forhorizontal sliding movement in a frame. The lock assembly comprises ablock having a vertical lock surface formed to engage the leading edgeof the sliding panel when the sliding panel is in closed position, withclearance to permit pivotal movement of the lock surface of the blockaway from the sliding panel thereby to permit free sliding movement ofthe sliding panel, and pivotal attachment means for pivotally attachingthe block at a position forwardly offset from the lock surface thereofto a horizontal surface of the frame and for providing limited verticalmovement of the block away from the horizontal surface. The block has ananchor means for releasably engaging a mating means in the frame offsetfrom the horizontal surface thereof. The anchor means is selectablyengageable and releasable by the combination of pivoting motion of theblock and motion toward and away from the horizontal surface. The locksurface of the block blocks the leading edge of the sliding panel toprevent any substantial sliding movement thereof when the anchor meansis engaged. Pivotal movement of the block is restrained when the anchormeans is engaged.

The present invention also provides a lock assembly for a horizontalsliding sashless window pane, one end of which overlaps, when closed, anadjacent end of a fixed sashless pane, in a frame including a sill inwhich the sliding sashless pane slides. The lock assembly comprises ablock, a pivot mechanism, a spring and an anchor. The block has a heightgreater than the vertical distance through which the sliding pane isfree to move, and is formed with a horizontal shoulder, and has avertical blocking surface of width substantially equal to the width ofthe sliding pane, for engaging the leading edge of the sliding pane withclearance sufficient to permit pivotal motion of the vertical blockingsurface away from and out of engagement with the leading edge of thesliding pane, and has a vertical neck surface extending rearwardly fromthe shoulder for engaging the side of the sliding pane over a portion ofits length from its leading edge. The pivot mechanism pivotally engagesthe block at a location forward of the vertical blocking surface forfixed pivotal attachment to the sill forwardly of and offset from theleading edge of the sliding pane. The pivot end of the block is providedwith mating vertical sliding surfaces which permit limited verticalsliding movement of the block away from the sill, and with a stop forrestraining vertical sliding movement of the block away from the sillthrough more than a predetermined maximum distance. The spring engagesthe pivot mechanism and the block to bias the block toward the sill andto resist vertical sliding movement of the block away from the sill. Theanchor is formed in or fixed to the block rearwardly of the pivotmechanism, and has an anchoring surface for releasably engaging a matingsurface in this sill to restrain pivotal movement of the block. Theanchor is released from engagement with the sill when the block is slidaway from the sill along the vertical sliding surface of the pivotmechanism through a distance less than the predetermined maximumdistance.

The invention will now be described, by way of example only, withreference to the following drawings, wherein like numerals refer to likeparts throughout, and in which:

FIG. 1 is an elevational view of a conventional sashless horizontalsliding window with the lock assembly of the present invention shownmounted on the sill thereof;

FIG. 2 is a plan sectional view taken along line II--II of FIG. 1;

FIG. 3 is a top plan view of the lock assembly of the present inventionshown mounted on the sill of a window;

FIG. 4 is a perspective view of the block element of the lock assembly;

FIG. 5 is a sectional elevational view taken along line V--V of FIG. 3;

FIG. 6 is a partially cut-out elevational view of the lock assemblyshown in its lifted position;

FIG. 7 is a transverse sectional view taken along line VII--VII of FIG.3.

FIG. 8 is an elevational view of an alternative embodiment of the lockedassembly, shown in its lifted position;

FIG. 9 is a sectional elevational view of a further alternativeembodiment of the locked assembly, shown in its anchored position.

FIG. 10 is a top plan view of the further alternative embodiment, shownin its open position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

It is to be understood when construing this disclosure and the claimsappended thereto that all references therein to terms suggestingrelative positioning of various components of the lock assemblyvis-a-vis a window assembly, such as "leading edge", "rearwardly","vertical" and "forwardly offset", are expressed relative to thepositioning of the lock assembly when it is mounted on a window assemblyoriented in its most common conventional configuration. Since the windowassembly could conceivably be oriented otherwise, these terms are meantto be construed relatively, not absolutely, in both this disclosure andthe claims appended hereto.

FIG. 1 illustrates a sashless horizontal sliding window designatedgenerally as 10, which comprises fixed sashless pane 11 and slidingsashless pane 12 mounted in a frame 13 having jambs 14 and sill 15 uponwhich is mounted the lock assembly of the present invention designatedgenerally as 16.

FIG. 2 illustrates the approximate mounting position of lock assembly 16on sill 15. Sliding pane 12 is in its closed position, and lock assembly16 is in its locked or anchored position.

FIG. 3 is a top view of the preferred embodiment of the presentinvention. Lock assembly 16 is shown attached to sill 15 in its lockedor anchored position by the solid lines, and in its opened position bythe dotted lines. Lock assembly 16 comprises block 16, pivotalattachment means 18, and anchor means 31 not shown in FIG. 3 but shownin FIG. 4, which is a perspective view of block 17.

Referring now to FIGS. 3 and 4, block 17 is formed with shoulder 21which defines vertical blocking or lock surface 19. Lock assembly 16should be mounted on sill 15 such that when the sliding pane 12 iscompletely closed and lock assembly 16 is in its anchored position, locksurface 19 engages the leading edge 20 of the sliding pane, withclearance sufficient to permit pivotal motion of the lock surface 19away from and out of engagement with leading edge 20. Such clearancebetween lock surface 19 and leading edge 20 should be generally a smallfraction of an inch, depending upon the width of lock surface 19, toallow the corner of lock surface 19 to clear the corner of leading edge20, as block 17 is pivoted between its anchored and open positions.

Block 17 is preferably provided with two symmetrically formed andlocated shoulders 21 and 22. Shoulder 21 provides a locking surface fora sliding pane mounted to the right of the fixed pane, when viewed frominside the dwelling, as shown in FIGS. 1-3, whereas shoulder 22 providesa locking surface for a sliding pane mounted to the left of the fixedpane, when similarly viewed. Lock assembly 16 may therefore be used foreither type of window, and as well, it may be mounted either on thebottom sill, as shown in the figures, or on the top sill (i.e. the tophorizontal member of the window frame which is also known as the head),virtually out of sight. Such symmetry also allows a window to be doublysecured by two lock assemblies, one mounted on the head and the othermounted on the sill.

Forward end 23 of the block assembly is provided with rounded or beveledcorner 24 which allows block 17 to be pivoted in a horizontal planeabout pivot point 25 without interference from fixed plane 11. Corner 26is provided for similar reasons to allow block 17 to be mounted andpivoted for left-to-right opening windows.

Block 17 preferably includes condensation lock means 27 as shown in FIG.3, which may comprise a resilient pad or flap extending from locksurface 19. Block 17 is shown in FIG. 4 without such condensation lockmeans.

As shown in FIG. 4, block 17 may comprise vertical neck surface 28extending rearwardly (i.e. away from the pivot point) from shoulder 21.Neck surface 28 engages a portion of the side of sliding pane 12 whenlock assembly 16 is in its anchor position, either by direct physicalcontact between itself and sliding pane 12, or by pressing condensationblock means 27 into physical contact with sliding pane 12 as shown inFIG. 3.

Block 17 may further include vertical head surface 30 which is formed toengage, in the sense of being closely adjacent to or bearing against, aportion of the side of fixed plane 11, when block 17 is in its anchorposition.

The purpose of neck surface 28 and head surface 30 is to provideresistance against movement of the sliding and fixed panels respectivelytowards the lock assembly in the direction perpendicular to the plane ofsliding movement of the sliding window (i.e. "inward" movement).

In order to ensure that neck surface 28 and head surface 30 properlyengage the sliding and fixed panels respectively, the width of locksurface 19 should be selected to be substantially the same as the widthof leading edge 20 of sliding pane 12. In those cases in which slidingpane 12 is not sashless but includes a sash, the width of surface 19should approximately equal the width of the sash.

The height of surfaces 19, 28 and 30 of block 17 are preferably selectedto be between 1/2" and 1", and must in any event be high enough toprevent the panes from being slid inwardly over the top of the lockassembly when it is in its anchored position. Having a relatively thickblock (i.e. relatively high lock, neck and head surfaces) increases theeffectiveness of the lock assembly against forced entry, for severalreasons. The relatively large surface area of contact between block 17and leading edge 20 provided by surface 19 spreads out the forcegenerated by an attempt at forced entry, thus reducing the pressure andthe chances of the glass pane fracturing against the lock surface. Ahigh block also reduces the possibility of the glass being slid inwardlyover the top of the lock assembly itself. A high block is alsoconvenient in that it allows for the block itself to be used as a handlefor manipulating the locked assembly. A large block also acts as aneffective visual deterrent against forced entry.

Block 17 is to be mounted on sill 15 such that pivot point 25 isforwardly offset from the leading edge 20 of sliding pane 12 when sameis in closed position, in the sense that the pivot point 25 is situatedalongside the fixed panel 11 rather than alongside the sliding panel 12.It is believed that the forward orientation of the pivot point relativeto the leading edge of the sliding panel when closed is advantageousover those lock mechanisms, such as the lock disclosed in Canadian Pat.No. 547,454 noted above, having pivot points located rearwardly of theleading edge of the sliding pane when closed, since application of alateral force to the sliding panel, especially in cases of slightmisalignment wherein the blocking surface of the lock is not exactlyperpendicular to the plane of the sliding panel, tends to pivot theblock of the present invention further towards the fixed panel, ratherthan away from same as would be the case for mechanisms having arearward pivot point.

Referring now to FIG. 5, anchor means 31 is preferably an anchor peg ofcircular cross-section formed in the bottom of block 17 rearwardly ofpivotal attachment means 18. Anchor means 31 releasably engages a matingmeans 32 offset from the surface of sill 15. Mating means 32 may be ahole located and dimensioned to accept anchor means 31 when block 17 hasbeen pivoted towards window 10 such that surfaces 19, 28 and 30 engagefixed and sliding panes 11 and 12 as described above. Anchor means 31,when engaged with mating means 32, prevents block 17 from being pivotedaway from the window in response to a forced entry attempt. Suchengagement also anchors the block 17 against movement thereof inresponse to a lateral force being applied to the sliding pane 12, or inresponse to an inwardly directed force being applied to either pane.

The depth of anchor means 31 is preferably from 1/4" to 1/2". Anchormeans 31 may, however, be considerably deeper, unlike the correspondinganchor means in a lever-action type of mechanism, whose depth isnecessarily limited to only a small fraction of an inch.

Pivotal attachment means shown generally as 18 may include fastener 33which extends through cavity 34 in a forward portion of block 17 intosill 15, when lock assembly 16 is in its mounted position. The bottomportion of block 17 may be provided with cylindrical anchoring sleeve 35which surrounds fastener 33. Block 17 may include spring supportshoulder 36 which divides cavity 34 into a wider region 37 and anarrower region 38, so as to support spring 39, which is positioned inwider region 37, between shoulder 36 and head 40 of fastener 33. Spring39 acts to bias block 17 towards sill 15. Fastener 33 may be aconventional wood screw having a flat head, or a wood screw and washerassembly. A hole must be made in sill 15 in order to accommodateanchoring sleeve 35.

The depth of wider region 37 and the nature of spring 39 are selected toallow block 17 to be moved through a predetermined maximum verticaldistance, which must be great enough to allow block 17 to be lifted faraway from the sill to disengage anchor means 31 from mating means 32.

To operate lock assembly 16 from its anchor position to its openposition, a "lift and twist" motion is employed (unless the lockassembly is mounted at the top of the frame, in which case the blockmust be lowered rather than lifted). That is, referring to FIGS. 3, 5and 6, lock assembly 16 is moved from its anchored position shown inFIG. 5 to its open position, shown by the dotted lines in FIG. 3, byfirst moving block 17 vertically a limited distance away from the sillalong the longitudinal axis 29 of fastener 33, thereby compressingsprings 39 into a compressed state 41 as shown in FIG. 6, such thatanchor means 31 clears mating means 32; and by next pivoting block 17about longitudinal axis 29 away from window assembly 10, to allowsliding pane 12 to be opened without interference with block 17.

It will be appreciated from the above description that pivotalattachment means 18 functions:

(1) to attach block 17 to sill 15;

(2) to bias block 17 against sill 15;

(3) to allow block 17 to be lifted to provide clearance between anchormeans 31 and mating means 32;

(4) to allow block 17 to be twisted towards or away from window 10; and

(5) to act as a second anchoring means, in addition to anchor means 31.

Referring now to FIGS. 4, 6 and 7, shoulder 21 and shoulder 22 need notnecessarily extend completely down the sides of block 17. Rather, it maybe preferable, in order to allow the lock assembly 16 to be used inassociation with certain types of commercially available windows havinga track mechanism or other obstruction running the length of at leastthe fixed pane, that portions 42 of shoulder 22 and shoulder 21 beremoved to allow clearance between block 17 and such track mechanism orobstruction.

An alternative embodiment of the lock assembly of the present inventionis shown in FIG. 8. Lock assembly designated generally as 50 comprisingmounting template 51 in addition to block 52 and pivotal attachmentmeans 53. Block 52 and pivotal attachment means 53 are similar to block17 and pivotal attachment means 18 respectively of preferred embodiment16. The anchor means of lock assembly 50 comprises cavity 54 formed inblock 52, rather than a peg projecting therefrom as in the case of thepreferred embodiment. Cavity 54 is dimensioned to accommodate peg 55which projects upwardly from mounting template 51. An aperture foraccepting a fastener 56 extends through peg 55. Block 52 is providedwith anchoring sleeve 58 extending a distance from the block less thanthe height of template 51, dispensing with the need to provide the sillwith a hole to accommodate sleeve 58. Template 51 is provided withaperture 57 dimensioned for sliding and pivoting engagement withanchoring sleeve 58.

A further alternative embodiment of the present invention is illustratedin FIGS. 9 and 10 and is designated generally as 60. Lock assembly 60comprises block 61, pivotal attachment means 62, anchor means 63, andmating means 64. Block 61 differs from block 17 in that the anchor means63 of block 61 is a cavity formed therein located rearwardly of thepivot point. Mating means 64 is a male insert which, when installed inthe sill, has a portion which projects above the surface of the sill andwhich is dimensioned to releasably engage cavity 63.

Block 61 also differs from block 17 in that it does not include astructure similar to anchoring sleeve 35. Accordingly, it is notnecessary to make (e.g. drill) a hole in the sill to accommodate sleeve35, as it is in the case of the preferred embodiment. Pivotal attachmentmeans 62 is similar to pivotal attachment means 18.

The particular advantages of each of the above embodiments will beapparent. The preferred embodiment consists of only three componentparts, the block, a fastener and a spring. It also includes an integralcondensation lock. The alternative embodiment includes a mountingtemplate, which reduces the chances of improperly installing the lockassembly. The further alternative embodiment includes a block ofrelatively simple construction. The alternative embodiments do notrequire any sill preparation in the nature of forming anchoringapertures.

A number of further variations and combinations of the three embodimentsshown in the figures are possible. For example, sleeve 35 of thepreferred embodiment may be dispensed with. Head surface 30 could beeliminated if resistance to inward movement of the sliding pane was notnecessary, which may be the case for certain applications. Block 17 neednot of course be symmetric, and may be formed with only a single locksurface. Condensation lock means 27 could alternatively extend from necksurface 28, rather than lock surface 19.

Furthermore, while the lock assembly has been illustrated and describedwith reference to and for use with a sashless horizontal sliding window,it will be readily apparent that it could be used for windows withsashes, and further, with other horizontal sliding closures, such assliding glass doors. It could also be used to secure sliding closureswhich are oriented at an angle to the horizontal, or even with slidingclosures which are oriented to slide vertically.

It will therefore be apparent to those skilled in the art that variousmodifications of the embodiments shown and described can be made withoutdeparting from the scope of the present invention, which is defined inthe claims appended thereto.

I claim:
 1. A lock assembly for a sliding closure having a fixed panel(11) and a sliding panel (12) mounted within a frame (13) for slidingmovement along a predetermined direction of movement within said frame;said sliding panel (12) movable along said direction between a closedposition and an open position with said sliding panel presenting aleading edge (20) generally transverse to said direction of movement;said assembly comprising:a block (17); pivot means (18) for pivotallyattaching said block (17) to said frame (13) with a pivot axis (25)disposed on a side of said leading edge (20) away from said openposition with said pivot axis generally perpendicular to said directionof movement; said block (17) pivotable about said axis between a lockposition and an unlocked position; said block (17) having a lock surface(19) opposing said leading edge (20) when said block (17) is pivoted tosaid lock position and said sliding panel (12) is in said closedposition with said lock surface (19) spaced from said leading edge (20)a distance to present a clearance sized to permit passage of said locksurface (19) through said clearance as said block (17) is pivoted fromsaid lock position to an unlocked position; anchor means for restrainingsaid block (17) from pivotal movement when said block (17) is in saidlocked position and comprising cooperating mating elements (31, 32) onsaid block member and said frame with said elements (31, 32) free toslide relative to one another in a straight path parallel to said pivotaxis, said mating elements movable a predetermined stroke between acaptured position and a free position with said elements (31, 32) insaid free position free to move relative to one another perpendicular tosaid pivot axis and with said elements (31, 32) in said capturedposition restrained from movement other than movement in said straightpath; and said pivot means including means for moving said block awayfrom said frame in a path parallel to said straight path a distancegreater than said stroke.
 2. A lock assembly as defined in claim 1,wherein the block also has a vertical neck surface formed to bepositioned closely adjacent a portion of the side of the sliding panelwhen the anchor means is engaged, to provide resistance to movement ofthe sliding panel in the direction perpendicular to the plane of slidingmovement of the sliding closure.
 3. A lock assembly as defined in claim2, wherein the block also has a head surface formed to be positionedclosely adjacent a portion of the side of the fixed panel when theanchor means is engaged, to provide resistance to movement of the fixedpanel in the direction perpendicular to the plane of sliding movement ofthe sliding closure.
 4. A lock assembly as defined in claim 3, whereinthe neck and head surfaces are of a dimension transverse to thedirection of sliding movement greater than the vertical distance throughwhich the sliding panel is free to move transverse to the direction ofsliding movement.
 5. A lock assembly as defined in claim 3, wherein thesurfaces are of a transverse dimension greater than about 1/2".
 6. Alock assembly as defined in claim 1, wherein the block is provided withresilient condensation lock means for compression against the slidingpanel when the anchor means is engaged, such that the sliding panel isforced into contact with an overlapped portion of the fixed panel.
 7. Alock assembly as defined in claim 6, wherein the condensation lock meanscomprises a resilient flap extending angularly from the lock surface,which is compressed between the sliding panel and the neck surface whenthe anchor means is engaged.
 8. A lock assembly as defined in claim 1,wherein the block also has a head surface formed to be positionedclosely adjacent a portion of the side of the fixed panel when theanchor means is engaged, to provide resistance to movement of the fixedpanel in the direction perpendicular to the plane of sliding movement ofthe sliding closure.
 9. A lock assembly as defined in claim 1, whereinthe lock surface is of a dimension transverse to the direction ofsliding movement greater than a distance through which the sliding panelis free to move transverse to the direction of sliding movement.
 10. Alock assembly as defined in claim 1, wherein the lock surface is of atransverse dimension greater than about 1/2".
 11. A lock assembly asdefined in claim 1, wherein the pivotal attachment means includes springmeans for biasing the block towards the captured position.
 12. A lockassembly as defined in claim 1, wherein the anchor means is an anchorpeg projecting from a surface of the block opposing the frame when thelock assembly is installed on the frame, and the mating means is a holein the frame dimensioned to accept the anchor peg.
 13. A lock assemblyas defined in claim 1, wherein the anchor means is a cavity in a surfaceof the block opposing the frame when the lock assembly is installed onthe frame, and the mating means is a peg projecting from the frame whichis dimensioned to be inserted in the cavity.
 14. A lock assembly asdefined in claim 1, wherein the pivotal attachment means includes afastener and a spring, and wherein the block has an aperture having ashoulder which defines a larger cavity adjacent a surface of the blockaway from the frame when installed, said fastener having a head endopposing said shoulder, the spring being mountable within the largercavity between the shoulder and the head of the fastener.
 15. A lockassembly as defined in claim 1, wherein the block has two symmetricallock surfaces.
 16. A lock assembly as defined in claim 1, wherein theblock is of sufficient transverse dimension to function as a handle formanipulating the lock assembly from its anchored position to itsunanchored position.
 17. A lock assembly as defined in claim 1, whereinthe lock is provided with rounded corners at the end adjacent the pivotpoint, to provide clearance between the block and the fixed panel whenthe block is pivoted.
 18. A lock assembly as defined in claim 1, furthercomprising a mounting template having a projection extending therefromfor engaging the anchor means.
 19. A lock assembly as defined in claim1, wherein the block includes means for providing clearance between theblock and mounting tracks or other obstruction located on the framealong the length of the fixed panel.
 20. A lock assembly as defined inclaim 1, wherein at least the side of the block positioned adjacent thepanels when the block is mounted and in its anchor position has formedtherein a transverse shoulder which forms the lock surface.
 21. A lockassembly for a horizontal sliding sashless window assembly having aframe including a lower horizontal sill with said frame defining awindow opening; a fixed sashless pane disposed within said frame andcovering a portion of said window opening and a sliding sashless panereceived within said frame and slideable on said sill between a closedposition with said sliding pane covering an exposed portion of saidopening not covered by said fixed pane and said sliding panehorizontally slideable to an open position to open said exposed portion;said fixed and sliding pane disposed within said frame and sized suchthat said sliding pane has a portion thereof overlapping said fixed panewhen in said closed position and terminating at a generally verticalleading edge adjacent said fixed pane with said overlapping portionincreasing in size as said sashless pane is moved to an open position;and with said sliding pane free for limited vertical movement withinsaid frame; said lock assembly comprising:a block; pivot means forpivotally securing said block to said sill to pivot about a verticalaxis disposed opposing said leading edge when said sliding pane is in aclosed position and with said block pivotable between a locked positionand unlocked position; said block shaped that when in said lockedposition to present a generally vertical lock surface opposing saidleading edge with said vertical lock surface having a horizontaldimension substantially equal to a horizontal dimension of said leadingedge; said block further provided with a shoulder having a blockingsurface opposing a vertical surface of said sliding pane generallyparallel to said direction of sliding movement; said lock surface spacedfrom said leading edge a distance to present a clearance with said locksurface free to pass through said clearance as said block is pivotedfrom said locked position to said unlocked position; anchor means forrestraining said block from pivotable movement when said block is insaid locked position comprising cooperating mating elements on saidblock and said sill with said mating elements slideably movable relativeto one another in a straight vertical line between a captured positionand a free position; said elements in said free position free to moverelative to one another in a direction perpendicular to said pivotalaxis and with said elements in said captured position restrained frommovement relative to one another in a direction other than along saidstraight vertical line; said pivot means in said block provided withmating vertical sliding surfaces permitting vertical sliding movement ofsaid entire block away from said sill in a direction parallel to saidstraight vertical line of movement of said anchor means mating elementswith said pivot means mating surfaces permitting vertical movement atsaid pivot axis a distance that is at least as great as a stroke of saidanchor means between said capture and free positions; stop meansrestraining vertical sliding movement of the block from the sill frommoving more than a predetermined maximum distance; and a spring engagingsaid pivot means and said block for biasing said block toward the silland resisting vertical sliding movement of said block away from saidsill.
 22. A lock assembly as defined in claim 2, wherein the block isformed with two symmetrically formed and located shoulders so that theassembly can be mounted for use with a sliding panel mounted on eitherside of the fixed panel.
 23. A lock assembly as defined in claim 2,wherein the anchor is a peg for engaging a hole in the sill.
 24. A lockassembly as defined in claim 2, wherein the anchor is a cavity forengaging a peg projecting outwardly from the surface of the sill.
 25. Alock assembly as defined in claim 2, wherein the blocking surface isprovided with a resilient pad for compression against the side of thesliding pane, thereby tending to force the sliding pane into contactwith the overlapping fixed pane.
 26. A lock assembly as defined in claim2, wherein the forward end of the block is provided with roundedvertical corner surfaces.